While we've done most of the work for you and selected an inexpensive, yet quality set of springs that you can choose, we'll detail generally what's being upgraded with the new Ender 3 V2 springs.
The upgraded springs should be the same length as your previous springs, so you do not need to adjust the Z-axis limiter switch after installing them. For the Ender 3 V2, they should be 20mm.
The upgraded springs need to be more rigid than the originals so that they reduce the vibration during printing and increase the overall consistency of your prints.
The shape of the springs makes a huge difference when it comes to shifting during printing and spring movement. The springs we selected have a flat top and bottom versus the stock Ender 3 V2 springs rounded top and bottom. This greatly reduces the springs' movement during printing.
Again, here are the springs we've tested and recommend for the Ender 3 V2.
Do not remove the entire build plate so that you can avoid harming the heating element wiring at the back-left.
I recommend starting at the back-left for this.
Carefully, lift each corner enough to replace all four springs individually.
Only after you've replaced all 4 springs, should you reattach each knob to the bed screw. This time you will turn the knobs counter-clockwise to tighten them.
The new springs for your Ender 3 V2 will be much stiffer, which should be immediately noticeable upon tightening.
If you've been using the stock springs for any length of time, then you should know how to level your bed by now. Lucky for you, now you won't need to level your bed between prints nearly as often!
Check out our guide on the best way to level the bed on the Ender 3 V2 if you're relatively new to all of this!